Dining with the dinosaurs proved a ripping tale

Tyrannosaurus rex was a "shake feeder" which ripped its prey apart by holding victims in its huge jaws and rapidly swinging its skull from side to side, or up and down, a scientist told the British Association's Annual Festival Of Science yesterday.

This shaking either ripped huge mouthfuls of flesh off the skeleton or was used to dismember the body, snappingbones and tearing off limbs, said Dr Pheagarten Lingham-Soliar of the Russian Academy of Scientists. It is a method of feeding used today by sharks, crocodiles and killer whales.

However, Dr Lingham-Soliar He has no solid proof; like so much dinosaur lore, hysteria mounts to intelligent speculation.

Its starting points are that the huge, bipedal carnivore which became extinct 67 million years ago had tiny forelimbs and an enormous skull and teeth. These minuscule arms were too puny to grasp struggling prey while the skull was so big in order to provide attachment areas for massive neck muscles used in the vigorous shaking.Rows of teeth the size of carving knifes would rip through flesh and sinew as the prey was swung violently around.

Dr Lingham-Soliar, editor of a Moscow based palaeontology journal and a specialist in functional anatomy, said Steven Spielberg got much of his dinosaur details right in Jurassic Park (he has yet to see this summer's sequel).

In the film, T. rex is seen shaking smaller dinosaurs to death - as well as a lawyer.

So why did the seven-ton dinosaur, which stood 15ft tall, have such tiny forelimbs? The scientist believes it was because T. rex's ancestors had less and less use for them, so evolution reduced their size.

Perhaps they were used to help get it up on to its hind legs after lying down.

Dr Lingham-Soliar rejects the theory of some palaeontologist that T. rex was mainly a scavenger feeding on the remains of animals killed by other predators. "An animal built like that is no scavenger," he said. He guesses it could run at 30mph.

Tiny, floating soap bubbles filled with air and helium have helped uncover the secrets of the flight of birds, which are all believed to have descended from an early dinosaur. Biological aerodynamics expert Professor Jeremy Rayner explained how his group at Bristol University had been using these bubbles to study the all-important air vortices left by flying birds.

The bubbles hang motionless in the air in the laboratory until a bird flaps through them. Their movement is then captured on film and used to analyse the precise shape and movement of the vortices.

Understanding the behaviour of these high energy air movements is essential to explaining the lift and forward propulsion and estimating the energy consumption of flapping flight.